No abstract

One possible solution of combating issues posed by climate change is the use of the High Temperature (HT) Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) in some applications. The typical HT-PEMFC operating temperatures are in the range of 100e200 o C which allows for co-generation of heat and power, high tolerance to fuel impurities and simpler system design. This paper reviews the current literature concerning the HT-PEMFC, ranging from cell materials to stack and stack testing. Only acid doped PBI membranes meet the US DOE (Department of Energy) targets for high temperature membranes operating under no humidification on both anode and cathode sides (barring the durability). This eliminates the stringent requirement for humidity however, they have many potential drawbacks including increased degradation, leaching of acid and incompatibility with current state-of-the-art fuel cell materials. In this type of fuel cell, the choice of membrane material determines the other fuel cell component material composition, for example when using an acid doped system, the flow field plate material must be carefully selected to take into account the advanced degradation. Novel research is required in all aspects of the fuel cell components in order to ensure that they meet stringent durability requirements for mobile applications.

Replacing fossil fuels with energy sources and carriers that are sustainable, environmentally benign, and affordable is amongst the most pressing challenges for future socio-economic development.

No abstract

No abstract

h i g h l i g h t s < This study focuses on generating important ex-situ GDL parameters. < The paper highlights the various types of commercial GDLs and discusses their characteristic variations. < The paper shows the relationship between several ex-situ GDL parameters. < The study explores the effect of PTFE loading and MPL presence upon the ex-situ characteristics of the GDL. < This study emphasizes the need of parameters optimisation in GDL design and fabrication. a b s t r a c tThis paper presents the first part of a complete ex-situ characterisation of a wide range of commercial Gas Diffusion Layers (GDLs) used in low temperature and high temperature Proton Exchange Membrane (PEM) fuel cells. Physical and electrical characteristics of the GDLs are reported. The results show that the substrate structure has a significant effect on the mechanical and electrical properties of the GDL. Moreover, the Micro Porous Layer (MPL) structure determines the roughness of the surface, and affects the permeability and porosity of the GDL. It was found that the substrate treatment with PTFE affects the GDL characteristics; PTFE loading increases the GDLs hydrophobicity and permeability, however, decreases its overall porosity and resistivity. Adding a MPL to the substrate, results in a decrease in porosity and permeability and an increase in resistivity. The contact resistance of the GDL and the bipolar plate increases when the GDL thickness and PTFE loading are increased. This technical paper shows a close relationship between GDL materials and their physical characteristics and highlights the importance of optimising GDLs for fuel cell applications.

No abstract

No abstract